1. Field of the Invention
This invention relates to a so-called pre-winding type photographic camera in which the whole of the film in a film magazine loaded in the camera is taken up once around the film take-up spool of the camera (pre-winding mode operation) and the film is then rewound into the magazine by one frame each time a picture is taken (photographing mode operation), and more particularly to a mode changing mechanism for such a pre-winding type photographic camera.
2. Description of the Prior Art
In the pre-winding type photographic camera, a mode changing mechanism for changing the operational mode of the camera from the pre-winding mode operation to the photographing mode operation is required. In order to automatically actuate the mode changing mechanism, means for charging the mode changing mechanism with actuating force becomes necessary. There has been proposed a pre-winding type photographic camera in which the actuating force is manually produced. However, such camera is disadvantageous in that the user is apt to forget to charge which could result in missing a shutter chance, or the user can mistake the inactiveness of the camera due to his forgetting to charge for a mechanical failure and open the backlid and spoil the film.
Thus there has been proposed a system in which the charging is accomplished in response to opening and closure of the backlid. However, this system gives rise to a problem that when the backlid is opened and closed by mistake while the camera is in the photographing mode state, the mode is changed to the pre-winding mode to wind the exposed part of the film, i.e., the part which has been rewound into the magazine, around the take-up spool, thereby causing the possibility of double exposure.
In order to avoid the possibility that the mode is changed when the backlid is opened by mistake, there has been proposed a system in which the charging is accomplished in response to insertion of the film magazine and accordingly the operational mode cannot be changed when the backlid is opened by mistake unless the magazine is once taken out and then inserted again. However, this system is disadvantageous in that the magazine is always in contact with a member by way of which the mode changing mechanism actuating force is charged, and accordingly it is difficult to keep the correct position of the magazine due to the pressure exerted on the magazine from the member.